I'm doing The Cornett's Call and have reached the step to meet Gwenfin, except she's never been where she is supposed to be. Not outside by the temple door, not inside with the statue. I've opened up the door with the Cornett of Waves and I've even found the Cornett of Depths, but this step of the quest can't complete.

Inside Ruins

Outside door

Quest Text

 

Don't know why she isn't there. But you don't need to meet her. You can carrry on with the quest and find the "real" temple in the Old City and use the conches there. Then go back to Dereo. The quest would even resolve if you never talked to Dereo before.